Prevalence and risk factors for postoperative delirium in a cardiovascular intensive care unit.

BACKGROUND Delirium after cardiac surgery is a common complication in cardiovascular intensive care units. The prevalence of delirium and its likely risk factors have not previously been explored in a single sample of postoperative cardiac patients in an intensive care unit. OBJECTIVE To compare a variety of characteristics in patients with and without delirium and to identify risk factors associated with delirium in patients hospitalized in an intensive care unit after cardiac surgery. METHODS A retrospective chart review was used to collect data on 288 patients who had open heart surgery during the period 2004 to 2005 at Chang Gung Memorial Hospital in northern Taiwan. A researcher-designed checklist of 52 patient-related risk factors for delirium was used to collect preoperative, intra-operative, and postoperative data. All patients were assessed by psychiatrists, and delirium was diagnosed according to criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition. Data were analyzed via univariate analysis and multivariate logistic regression. RESULTS The prevalence of postoperative delirium was 41.7%. Patients with and without delirium differed significantly on 29 variables. Four postoperative factors, hematocrit less than 30%, cardiogenic shock, hypoalbuminemia, and acute infection, were significant, independent predictors of postoperative delirium. CONCLUSIONS The results of this study can be used to develop a revised checklist of 29 preoperative, intraoperative, and postoperative risk factors for delirium, with special attention to the 4 predictive postoperative factors. Use of such a checklist may facilitate the ability to prevent or detect delirium early and provide suitable treatment.